Windows setevent processsing
- by Waldorf
I wonder how setevent is handled internally within Windows.
I have the following situation
Std::thread thread loop which executes while std::atomic == true
Inside the loop is a waitforsingleObject which sleeps infinite in alertable state.
A function stopThread() which does the following:
- Clears the atomic bool
- Calls Setevent on the event object
- Calls thread.join
This often hangs, I get the impression that setevent has still some work to do in the current thread, while join blocks
the current thread.
If I add an additional Boolean in the thread which is set after waitforsinlgleObject and I wait for this to be set before calling join()
Everything seems to work ok.
Code (error checking omitted here)
Init code/declarations:
HANDLE m_WakeupThreadEvent;
std::atomic<bool> m_ReceiverEnabled;
m_WakeupThreadEvent = CreateEvent(NULL, false, false, "RxThreadWakeupEvent" );
Thread code:
while(m_ReceiverEnabled)
{
DWORD rslt = WaitForSingleObjectEx(m_WakeupThreadEvent, INFINITE, true);
// Here some checking for rslt;
}
function code:
m_ReceiverEnabled = true;
SetEvent( m_WakeupThreadEvent )
m_Thread.join()
Is there some explanation for this behavior ? I could not find any details about the operation of setEvent()